1. Field of the Invention
The present invention relates to a structure of an image display apparatus which forms an image with an electron-emitting device.
2. Related Background Art
In this type of image display apparatus, an electron emitted from an electron-emitting device is transmitted through an accelerating electrode which accelerates the electron, and a phosphor member made of a fluorescent material and the like is irradiated with the electron. In the phosphor member, a bright spot (light-emission spot) is generated in a region irradiated with the electron, and the image is formed by the plural bright spots (hereinafter sometimes individual phosphor member is referred to as pixel).
However, the electrons with which the phosphor member is irradiated are scattered on the phosphor member (hereinafter the electron is referred to as “scattered electron”). When the scattered electrons are incident to the adjacent pixel again, a phenomenon called halation in which the scattered electrons causes the light emission from the adjacent pixel is generated, which results in troubles such as color drift.
Therefore, recently many technologies which suppress the halation are disclosed. For example, U.S. Pat. No. 5,639,330 discloses the image display apparatus in which a thickness of the accelerating electrode is adjusted in order to suppress efficiency of re-incidence of the scattered electron to the phosphor member of not more than 30%.
However, in the image display apparatus disclosed in U.S. Pat. No. 5,639,330, the light emission caused by the electrons other than the scattered electrons is also suppressed while the light emission caused by the halation is suppressed. Namely, the light emission caused by the proper electrons emitted from the electron-emitting device is suppressed. Therefore, since the intended brightness cannot be obtained, further improvement is demanded from the viewpoints of high brightness and high contrast.